The present invention relates in general to the design of forced air heating and air conditioning systems and the problem of poor or insufficient air delivery and circulation. More specifically the present invention relates to a fan-equipped air delivery vent which can be used for increased air delivery and enhanced air circulation in those situations and in those locations where the conventional forced air heating or air conditioning is not adequate.
A centralized forced air handling system represents the preferred choice and the most commonly installed type of system. The design of such a system and its installation provide a number of benefits for the heating and cooling of a structure, such as a residence. However, there are also certain shortcomings, principally air delivery and circulation problems associated with such centralized systems. The air delivery and circulation problems are created by the use of a single, central blower to force the heated or air conditioned air up through the network of air ducts to the various rooms and living spaces of the structure. The air duct paths differ from room to room in both their specific routing as well as their length or distance from the central blower.
Realizing that the forced air, whether heating or cooling, will not flow in a uniform and balanced fashion equally to every corner of every room, there exists the potential for certain rooms and spaces which are farther from the blower to receive inadequate air flow and as a result inadequate heating or cooling. Sometimes the various curves and bends of the air ducts contribute to the inadequate or insufficient air delivery. In other arrangements, it may simply be the distance from the central blower which is the primary contributor to inadequate air delivery. Regardless of the specific reasons, when the air delivery to a particular room or space is not sufficient to provide adequate heating in the winter and cooling in the summer, there is a need to improve upon the system so as to correct this problem. Merely increasing the air delivery (volumetric flow) rate from the centralized blower is not the answer. As indicated, there are only certain rooms and spaces which are receiving an adequate air flow. There are typically other portions of the structure which are in a more direct line with the blower and/or at a shorter distance away from the blower which are adequately heated and cooled. In some instances, these areas might already be receiving too much air flow due to the difficulties in trying to balance out the heating and cooling in all corners of a large structure, such as a two story home. In order to solve the problem of certain rooms or spaces being too cold in the winter and too warm in the summer, some corrective measure needs to be taken on a room-by-room basis.
Associated with inadequate air flow is the air circulation reality that cooler air settles in the lower regions of a room or structure and that warmer air rises. When dealing with a two story home, for example, this is another factor which influences whether all of the various rooms will be somewhat balanced as to their heating and cooling temperatures. As noted, since the central system relies on a single blower (air delivery device) to satisfy the air delivery requirements for all rooms, the chance for variations and inadequate air delivery to certain more remote rooms is relatively high. In order to solve the aforementioned problem which is associated with conventional forced air handling systems, designs have been conceived to introduce a supplemental flow of air (fan-driven) between the main blower and the room or space which has an insufficient air flow. Typically such designs are positioned near or in the air delivery duct which is associated with the particular room or space. Many of these supplemental designs are best described as fan-equipped air delivery devices and in certain arrangements are self-contained as a separate module.
While the following listed patents are typical of these earlier fan-equipped air delivery devices, each one represents a slightly different approach to the problem of air delivery and circulation:
______________________________________ PATENT NO. PATENTEE ISSUE DATE ______________________________________ 1,645,140 Herbruck Oct. 11, 1927 1,875,683 Waterbury Sep. 6, 1932 1,875,684 Waterbury Sep. 6, 1932 2,043,934 Spear Jun. 9, 1936 2,525,157 Trane Oct. 10, 1950 2,972,941 Bennett Feb. 28, 1961 3,099,201 Gottlieb Jul. 30, 1963 3,148,613 Koon Sep. 15, 1964 4,212,233 Shaffer Jul. 15, 1980 4,722,266 Deckert Feb. 2, 1988 4,754,697 Asselbergs Jul 5. 1988 4,846,399 Asselbergs Jul. 11, 1989 5,054,380 Hubbard Oct. 8, 1991 ______________________________________
Two additional devices are disclosed in the Fall 1994 issue of the "Improvements" catalog detailing "quick and clever problem solvers". On page 58 there is a model 49254-blower booster 2 offered for sale and on page 59 an in-duct booster fan. The devices detailed by the listed patents and by the "Improvements" catalog can, for the most part, be grouped into two general categories. In one category, a fan is simply placed in an existing conduit or duct prior to or upstream from the room register (vent). In the other category, the fan is preassembled into a module which is typically mounted onto the exterior of the room register. Often associated with each category are various brackets, baffles, conduits, and controls which have specific functions to control, route or in some way try to enhance the air delivery. While the objective of each design is to enhance the flow of air through a duct or conduit into a room or space, the specifics of the construction of each device and the functional subtleties of each device provide points of differentiation. These points of differentiation contribute to different patentable inventions.
Although several patents have been granted, there remain a number of shortcomings and drawbacks with each of these earlier inventions. For example, many of the earlier designs are fashioned on the theory of one-size fits all, without regard to the size of the room which is not getting adequate air flow. Other designs position the fan in a wide open area without any enclosure or shroud, thereby allowing inefficient air flow patterns and the recirculation of "dirty" air back into the fan by way of any clearance around the outermost tips of the fan blades. As to those earlier designs which provide only a constantly ON or OFF mode of operation, there is no ability to control when additional air flow should be provided based on the temperature within the room. As to those designs which mount externally to the existing vent, whether over or onto a wall or floor register, what results is a cumbersome device which interferes with the free movement into and out of the room and which restricts the positioning of furniture within the room.
As to those designs which are not modular or otherwise self-contained, the existing register must be removed and access provided to the interior of the air delivery duct. The additional attachment of various brackets and supports for positioning the fan in the duct must also be performed piece-by-piece and this results in a substantial inefficiency as to both cost and labor time.
After carefully reviewing all of the listed patents and evaluating the shortcomings and design inefficiencies with each, the present invention was conceived and perfected. The present invention is designed to accept one, two, three or more fans in the same sized, self-contained module, depending on room size requirements and vent opening/size restrictions. Therefore, while the register-sized modular unit maintains its external size and compatible fit within the floor or wall opening, the invention can be styled to accept a different number of fans. In this manner, the size of the room can be factored into the selection of the specific style of the present invention. The present invention is a modular design which includes a standard register. The present invention module is designed to fit conveniently and efficiently into the existing register opening, whether in a floor or wall. A thermostat control and separate ON-OFF switch enable the operation to be tailored to either heating or cooling requirements.
Importantly, the present invention also includes a rear enclosing panel which cooperates with fan shrouds to seal closed the flow avenues which might permit a recirculation path for "dirty" air. When dirty air is drawn back in across the tips of the fan blades, it reduces the life of the motor. The present invention handles only clean, filtered air directly from the furnace (or air conditioner). The air inlet apertures in the enclosing panel (one for each fan) are directly in line with the fan axis of rotation and in line with the exit flow path from each fan. This direct flow path contributes to the efficiency of the design and reduces the load on each fan.
The present invention also provides a selective combination of several unique features which have heretofore not been combined in any single device. This combination of features is novel and unobvious and provides various advantages over the prior art.